Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

3. To determine whether F₁​ plants are homozygous or heterozygous

Explanation:

The crossing of an F₁​ progeny with a homozygous recessive parental progeny is done in order to determine whether the progeny is homozygous or heterozygous for a character under consideration. This is called a test cross. Those that are heterozygous will have one dominant and one recessive allele individuals and those that are homozygous dominant will have two dominant alleles, and those that are homozygous recessive will have two recessive alleles.